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Steveromo 11-20-2013 01:47 PM

Gas Trimmer Engine Problems
I have a craftsman 2 cycle gas trimmer. Worked OK for 2 summers but trouble started late this summer. I was on the same gas that I got in the beginning of the summer. It stalled out while trimming one day, and would not restart. A week later, I changed the spark plug and cleaned the filter. It started easily, I revved it for a minute then shut it off to load up string. You guessed it, it did not restart. So I drained the gas, got a fresh can, and filled the tank. It started easily, I trimmed for about two minutes and it abruptly stalled again and would not restart. I pushed the primer so many times trying to restart I'm sure all the old gas is gone, but it still won't start. Any clue what it might be???

joecaption 11-20-2013 05:19 PM

About 90% of the time it's using ethanol gas that has messed up the lines and the carburetor.
I never mix more then 1 gal. at a time, always use nonethanol fuel and all my chainsaws, trimmers start every time.
You can now buy premixed nonethanol fuel or you can use an additive to counter act the effects of the ethanol.
Now your stuck with replacing or rebuilding the carburetor.

danpik 11-21-2013 11:55 AM

Look inside the fuel tank and see if there is a filter in there. All of my machines have them. I grab the hose in the tank with needle nose pliers and work the filter out. I spray carb cleaner thru them backwards to flush them out at least once every two years. I have a 27 year old leaf blower that is still on it's first filter and starts every time.

mj12 11-22-2013 10:50 PM

Never had much luck with craftsmen stuff. I had a craftsmen leaf blower that was basically brand new. I could never get that thing to run properly. You have to disassemble the whole thing too do anything to it. Most people just buy new every few years.

nvrfinished 12-14-2013 03:34 PM


Look inside the fuel tank and see if there is a filter in there. All of my machines have them. I grab the hose in the tank with needle nose pliers and work the filter out. I spray carb cleaner thru them backwards to flush them out at least once every two years.
I have to agree here. More than likely this is your issue. I've had to do the same thing for my equipment from time to time. It's almost always the filter when this happens.

Davejss 12-14-2013 06:20 PM

Premium gas and some Stabil will prevent 90% of future carb troubles.

Steveromo 04-29-2014 09:04 AM

Update: I tried a new spark plug, I cleaned the carburator, the fuel lines, the fuel filter, and the air filter but still no luck! When I prime, the fuel flows like it always did. When I pull the rope to start, it has plenty of resistance and it recoils back on the wheel just fine, but NOTHING happens. No sputter, no puff of exhaust, no churning of the engine. Zilch! I don't know engines at all, but I would assume that even a clog or fuel problem might yield a little sputtering when attempting to start. I just have a feel that it is something electrical in nature (like a car with a dead battery.) I experimented and took the spark plug out of it's socket. With the connector still attached I pulled to start in the dark and saw no spark. Is this a sign of something? Can I test the spark plug if I have no special tools? Are there any other potential causes? Thanks for the feedback!

danpik 04-29-2014 09:51 AM

The spark plug will not fire outside of the engine unless it is grounded to the engine. I do this sometimes with a jumper cable. I connect one lead to the metal body of the spark plug and the other end to a bolt on the engine. That will ground it just like it is threaded into the head.

With the plug out, try this...Put your thumb over the plug hole to seal it. Slowly pull the starter. If the culinder has good compression it will try to push your thumb off of the plug hole as the engine rotates. If it does not do this it could be a compression problem in the cylinder. There also could be a crankcase vacuum leak. Two stroke engines use the crankcase to push air/fuel into the cylinder.

47_47 04-29-2014 09:55 AM

The plug must be grounded to the engine metal to see if you have spark. Was the spark plug wet with un-burned fuel? Did you fiddle with any carb adjustment screws?

From posts still seems like fuel. What mix are you running? Remove your air filter, open the choke butterfly and spray in (2-3 seconds) worth of carb cleaner. Try to start.

Steveromo 05-03-2014 03:11 PM

Since all other fixes failed, I gave in and brought the trimmer to a small engine shop for evaluation. Mechanic attached an air pressure meter and informed me that my trimmer is reading 40-45 when it needs to be around 90 to start. Any attempt at repair would be too expensive. Trimmer is dead! I asked what could cause this and he said a poor mix of fuel/oil. I was very careful to always mix properly. If I decide to replace it with a similar model (I use the blower attachment for easy cleaning of trimmings) I intend to use the premixed fuel/oil to hopefully help it last more than 2 years. Thanks to all who posted replies!

Dave Sal 05-05-2014 11:54 PM

I've had a Craftsman two cycle weed wacker for about 10 years now and I am not at all careful when mixing gas and oil. Never had any problems starting it as long as I use fresh fuel..

danpik 05-06-2014 05:40 AM

Here is a link to how these little engines work.

while the oil mix in the fuel is critical to help lubricate the bearings in the crank case and ultimately all the other internal workings of the engine. a slight miss mix in the oil/gas ratio won't destroy one of these engines over night. In fact, I have accidently ran mine on just straight gas on occasion with no ill effects. I would not recommend doing it but it has been done. What needs to be kept in mind is that most of these $100 machines are basically throw away tools. These engines are not built with any real tight precision and in fact a lot of them use plastics in some of the engine components. The low compression reading the mechanic got is most likely from bad piston rings. They seem to be using poorer and poorer grades of material when they build these things

47_47 05-06-2014 06:07 AM

To add to what the others said, running a 2 stroke engine too lean will make it run hotter and gall the pistons.

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